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4 years ago

10. Name THREE conductors and insulators with examples from everyday use.

Physics

1 answer:

Anna35 [415]4 years ago

7 0

Answer:

Explanation:

Some common conductors are copper, aluminum, gold, and silver. Some common insulators are glass, air, plastic, rubber, and wood.

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a machine has an efficiency of 70 percent, how much work does the machine do when 20000 j of work is done on it a. 14000 b. 2060

Vlad [161]

Answer:

a. 14000

Explanation:

Given parameters:

Efficiency of the machine = 70%

Work done on machine = 20000J

Unknown:

Work done by machine = ?

Solution:

Efficiency of a machine is determined by;

Efficiency = $\frac{Work done by machine}{Work done on machine} x 100$

70 = $\frac{Work done by machine}{20000}$ x 100

70 = $\frac{work done by machine}{200}$

Work done by machine = 70 x 200 = 14000J

4 0

3 years ago

A 5.00×105-kg subway train is brought to a stop from a speed of 0.500 m/s in 0.400 m by a large spring bumper at the end of its

Lesechka [4]

This can be calculated with the law of conservation of energy. The kinetic energy Ek of the train is completely transformed to potential energy of the spring Ep which stops the train:

Ek=Ep

(1/2)*m*v²=(1/2)*k*x², where m is mass of the train, v is the velocity of the train, k is the force constant of the spring and x is the path the train went while being stopped and also the amount of length the spring compressed.
We solve for k:

(1/2)*m*v²=(1/2)*k*x², 1/2 cancel out:

m*v²=k*x², we divide both sides by x² and get k:

k=(m*v²)/x²={(5*10^5)*(0.5²)}/(0.4²)=781250 N/m

So the force constant of the spring is: k=781250 N/m.

5 0

4 years ago

How can the quantity of protons neutrons and electrons in an atom be determined

RideAnS [48]

Answer:

The atomic number tells you your protons a neutrons and you can find electrons by doing the atomic mass minus the atomic number

Explanation:

MAN

Mass-Atomic Number=Nuetrons

5 0

3 years ago

Two tiny, spherical water drops, with identical charges of -7.08 × 10-16 C, have a center-to-center separation of 1.00 cm. (a) W

galben [10]

Answer:

(a) Electrostatic force F=4.51×10⁻¹⁷N

(b) Number of electron n=4425 electrons

Explanation:

Given data

Charges q₁=q₂= -7.08×10⁻¹⁶C

Distance r=1.00cm =0.01 m

To find

(a) Electrostatic force F

(b) Number of electron n

Solution

For (a) Electrostatic force

From Coulombs law we know that

$F=k\frac{q_{1}q_{2} }{r^{2} }\\ As\\ q_{1}=q_{2}=q\\So\\F=k\frac{q^{2}}{r^{2} }\\F=(8.99*10^{9})\frac{(-7.08*10)^{-16})^{2}}{(0.01)^{2} }\\F=4.51*10^{-17}N$

For (b) number of electron n

The number of electron on the drop that giving it its imbalance is the total charge divided by charge of electron

As we now that charge of electron e= -1.6×10⁻¹⁹C

$n=q/e\\n=\frac{-7.08*10^{-16} C}{-1.6*10^{-19} C}\\ n=4425electrons$

3 0

4 years ago

A 2kg mass is moving at 3m/s. What is its kinetic energy?

Illusion [34]

<h2><u>KINETIC ENERGY</u></h2>

<h3>Problem:</h3>

» A 2kg mass is moving at 3m/s. What is its kinetic energy?

<h3>Answer:</h3>

$\color{hotpink} \bold{9 \: J} \\$

— — — — — — — — — —

<h3>Formula:</h3>

To calculate the velocity of a kinetic energy, we can use formula

$\underline{ \boxed{ \tt KE = \frac{1}{2} m{v}^{2} } }$

where,

v is the velocity in m/s
KE is the kinetic energy in J (joules)
m is the mass in kg

— — —

Based on the problem, the givens are:

KE (Kinetic energy) = ? (unknown)
m (mass) = 2 kg
v (velocity) = 3 m/s

<h3>Solution:</h3>

To get the velocity, substitute the givens in the formula above then solve.

$\: \: \tt KE = \frac{1}{2} m{v}^{2} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \tt \: KE = \frac{1}{2} \times 2 \times {(3)}^{2} \\ \tt \: \: \: \: \: \: \: \: \: \: \: \: \: \: KE = \frac{1}{2} \times(2\times 9) \\ \tt KE = \underline{ \boxed{ \blue{ \tt9 \: J}}}$

Therefore, the kinetic energy is 9 Joules.

3 0

2 years ago